package com.aidex.common.utils;


import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

public class AESUtils {
    private static final String KEY_ALGORITHM = "AES";

    private static final String DEFAULT_CIPHER_ALGORITHM = "AES/CBC/PKCS5Padding/";
    // private static final String DEFAULT_CIPHER_ALGORITHM = "AES/ECB/PKCS5Padding/";
    public static final String key = "zxxxzcvxiongxing";

    public static byte[] initSecretKey() {
        // 返回生成指定算法的秘密密钥的 KeyGenerator 对象
        KeyGenerator kg = null;
        try {
            kg = KeyGenerator.getInstance(KEY_ALGORITHM);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
            return new byte[0];
        }
        // 初始化此密钥生成器，使其具有确定的密钥大小
        // AES 要求密钥长度为 128
        kg.init(128);
        // 生成一个密钥
        SecretKey secretKey = kg.generateKey();
        return secretKey.getEncoded();
    }

    private static Key toKey(byte[] key) {
        // 生成密钥
        return new SecretKeySpec(key, KEY_ALGORITHM);
    }

    public static byte[] encrypt(byte[] data, Key key) throws Exception {
        return encrypt(data, key, DEFAULT_CIPHER_ALGORITHM);
    }

    public static byte[] encrypt(byte[] data, byte[] key) throws Exception {
        return encrypt(data, key, DEFAULT_CIPHER_ALGORITHM);
    }

    public static byte[] encrypt(byte[] data, byte[] key, String cipherAlgorithm) throws Exception {
        // 还原密钥
        Key k = toKey(key);
        return encrypt(data, k, cipherAlgorithm);
    }

    public static byte[] encrypt(byte[] data, Key key, String cipherAlgorithm) throws Exception {
        // 实例化
        Cipher cipher = Cipher.getInstance(cipherAlgorithm);
        // 使用密钥初始化，设置为加密模式
        cipher.init(Cipher.ENCRYPT_MODE, key);
        // 执行操作
        return cipher.doFinal(data);
    }

    public static byte[] decrypt(byte[] data, byte[] key) throws Exception {
        return decrypt(data, key, DEFAULT_CIPHER_ALGORITHM);
    }

    public static byte[] decrypt(byte[] data, Key key) throws Exception {
        return decrypt(data, key, DEFAULT_CIPHER_ALGORITHM);
    }

    public static byte[] decrypt(byte[] data, byte[] key, String cipherAlgorithm) throws Exception {
        // 还原密钥
        Key k = toKey(key);
        return decrypt(data, k, cipherAlgorithm);
    }

    public static byte[] decrypt(byte[] data, Key key, String cipherAlgorithm) throws Exception {
        // 实例化
        Cipher cipher = Cipher.getInstance(cipherAlgorithm);
        // 使用密钥初始化，设置为解密模式
        cipher.init(Cipher.DECRYPT_MODE, key);
        // 执行操作
        return cipher.doFinal(data);
    }

    private static String showByteArray(byte[] data) {
        if (null == data) {
            return null;
        }
        StringBuilder sb = new StringBuilder("{");
        for (byte b : data) {
            sb.append(b).append(",");
        }
        sb.deleteCharAt(sb.length() - 1);
        sb.append("}");
        return sb.toString();
    }

    /**
     * 将二进制转换成16进制
     *
     * @param buf
     * @return
     */
    public static String parseByte2HexStr(byte buf[]) {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < buf.length; i++) {
            String hex = Integer.toHexString(buf[i] & 0xFF);
            if (hex.length() == 1) {
                hex = '0' + hex;
            }
            sb.append(hex.toUpperCase());
        }
        return sb.toString();
    }

    /**
     * 将16进制转换为二进制
     *
     * @param hexStr
     * @return
     */
    public static byte[] parseHexStr2Byte(String hexStr) {
        if (hexStr.length() < 1) {
            return null;
        }
        byte[] result = new byte[hexStr.length() / 2];
        for (int i = 0; i < hexStr.length() / 2; i++) {
            int high = Integer.parseInt(hexStr.substring(i * 2, i * 2 + 1), 16);
            int low = Integer.parseInt(hexStr.substring(i * 2 + 1, i * 2 + 2), 16);
            result[i] = (byte) (high * 16 + low);
        }
        return result;
    }

    public static Cipher init128AESCipher(String sKey, int cipherMode) {
        //创建Key gen
        KeyGenerator keyGenerator = null;
        Cipher cipher = null;
        try {
            keyGenerator = KeyGenerator.getInstance("AES");
            keyGenerator.init(128, new SecureRandom(sKey.getBytes()));
            SecretKey secretKey = keyGenerator.generateKey();
            byte[] codeFormat = secretKey.getEncoded();
            SecretKeySpec key = new SecretKeySpec(codeFormat, "AES");
            cipher = Cipher.getInstance("AES");
            //初始化
            cipher.init(cipherMode, key);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
        } catch (InvalidKeyException e) {
            e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
        }
        return cipher;
    }

    public static void main(String[] args) throws Exception {
//        byte[] key = initSecretKey();
//
//        Key k = toKey(key);

        String data = "AES数据";
        System.out.println("加密前数据: string:" + data);
//        byte[] encryptData = encrypt(data.getBytes(), k);
        // String aes = parseByte2HexStr(encryptData);
        String aes = encryptByAES(data);
        System.out.println("加密后数据: byte[]:" + aes);
        System.out.println();
        // byte[] decryptData = decrypt(parseHexStr2Byte(aes), k);
        //System.out.println("解密后数据: byte[]:" + showByteArray(decryptData));
        System.out.println("解密后数据: string:" + decryptByAES(aes));

    }

    /***
     * 加密
     * @param original 需要加密的参数（注意必须是16位）
     * @return
     * @throws Exception
     */
    public static String encryptByAES(String original) throws Exception {
        // 获取Cipher
        Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);
        // 生成密钥
        SecretKeySpec keySpec = new SecretKeySpec(key.getBytes(), KEY_ALGORITHM);
        // 指定模式(加密)和密钥
        // 创建初始化向量
        IvParameterSpec iv = new IvParameterSpec(key.getBytes());
        cipher.init(Cipher.ENCRYPT_MODE, keySpec, iv);
        // cipher.init(Cipher.ENCRYPT_MODE, keySpec);
        // 加密
        byte[] bytes = cipher.doFinal(original.getBytes());

        return parseByte2HexStr(bytes);
    }

    /**
     * 解密
     *
     * @param encrypted 需要解密的参数
     * @return
     * @throws Exception
     */
    public static String decryptByAES(String encrypted) throws Exception {

        // 获取Cipher
        Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);
        // 生成密钥
        SecretKeySpec keySpec = new SecretKeySpec(key.getBytes(), KEY_ALGORITHM);
        // 指定模式(解密)和密钥
        // 创建初始化向量
        IvParameterSpec iv = new IvParameterSpec(key.getBytes());
        cipher.init(Cipher.DECRYPT_MODE, keySpec, iv);
        // cipher.init(Cipher.DECRYPT_MODE, keySpec);
        // 解密
        byte[] bytes = cipher.doFinal(parseHexStr2Byte(encrypted));

        return new String(bytes);
    }
}
